Cabin pressure regulator



June 25, 1946.

R. J. SCHROEDER CABIN PRESSURE REGULATOR Filed Nov. 25, 1944s'sheets-sneet 1 I N VEN TOR.

l2 IA 40 @o 55A T d. 6c Heofoff? June 25, 1946. R. J. scHRoEDx-:R2,402,681

CABIN PRESSURE REGULATOR Filed NOV. 23, 1944 v 3 Sheets-Sheet 2 Junev25, 1946. R, L SCHROEDER 2,402,681

CABIN PRES SURE REGULATOR Filed Nov. 25, 1944 3 Sheets-Sheet 3 PatentedJune 25, 1946 UNITED STATES PATENT OFFICE CABIN PRESSURE REGULATORRobert J. Schroeder, New Bremen, Ohio Application November '23, 1944,Serial No. 564,889

(ci. ca -1.5)

(Granted under the tot March 3, lass, as amended April 3o, 192s; 37o o.G. 757) 14 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

This invention concerns pressure regulators for controlling the pressureof air in pressurized aircraft cabins and compartments.

In pressure cabin aircraft the pressurization system used consists o!one ormore compartments designed to retain air under pressure, apressure source such as an air line from the engine supercharger or aseparate cabin supereharger, also an air ilow responsive control deviceto retain the rate of flow of supply air within the desired limits, andone or more air outflow valves or regulators in such cabins andcompartments to act automatically in throttling the outiiow of air tomaintain the desired cabin pressure.

' The system usually also includes an auxiliary relief valve and checkvalve to limit possible diiferential pressure between cabin andatmosphere to a safe value from a standpoint of cabin structure, andusually also includes a manually oper- Y able air outiiow control.

My invention as disclosed in this application involves the automaticcabin air outflow regulator or pressure regulator for controlling theoutflow oi air from the cabin. Such a cabin pressure regulator isutilized to retain the specific cabin pressure altitudes or cabinequivalent altitudes at the given flight altitudes, and the requirementsof the regulator and pressures vary according to the tactical use towhich the airplane is put. The requirement of cabin altitude in abombardment planev is graphically shown in Fig. l; and the requirementfor a tighter plane is similarly shown in Fig. 2; while the cabinpressures and flight pressures in in. Hg are shown in Fig. 3, for abetter illustration of these features. Other schedules of cabinaltitudes to be maintained for commercial planes are likewise similarlyreadily arranged and shown.

It may be observed from the graphic illustrations and from the followingdisclosures that in these instances a definite cabin altitude isrequired or is established at any given ilight altitude. For example: inthe case o! bombardment aircraft, as illustrated in Fig. 1, fromtake-oi!A to 8,000 ft. the cabin is at about the same absolute pressureas the ambient atmosphere. As ilight altitude increases to 35,000 ft.the cabin pressure or cabin-equivalent altitude is to remain at 8,000it.. as indicated by the line a-b in Figs. l and 3. an area being shownassociated with the line to indicate the allowable cabin pressuredeviation 56 from the selected constant pressure differential. Thedifferential pressure between the 8,000 ft. cabin altitude indicated atb and the 35,000 ft. flight altitude, indicated at c on the flightaltitude line of Figs. 1 and 3, is 7.45 p. s. i. or 15.17 in. Hg, andthe cabin altitude is to be such as will hold this dierential pressureas a, constant as the climb is continued to 40,000 ft. indicated by theline b-d, at which point d the cabin equivalent altitude is then 10,000it. As the climb is continued beyond 40,000 ft. the cabin pressureregulator is to maintain a cabin pressure or cabin equivalent altitudesuch that the ratio between the absolute pressures existing with a,10,000 it. cabin altitude and a 40,000 ft. flight altitude will be heldas a constant, as indicated by the cabin altitude line d-e, extendingsubstantially lparallel to the flight altitude line. y

Further requirement in military installations are that the rate ofchange of cabin altitude be limited to a given value regardless of nightaltitude' rate of changes, and that a manual override control beprovided in connection with the automatic cabin regulator. Furthermore,in some military aircraft an over-ride control is requiredV which willautomatically limit the cabin pressure to a given diierential pressurebetween thatoi the cabin equivalent altitude and of the flight altitude,as illustrated in Figs. 1 and 3 by the lines f-a and o-c, being shownherein as a selected differential pressure of substantially 2.75 p. s.i. or 5.6 in. Hg.

In the cabin pressure regulators so far in use in pressure cabinaircraft, such control as outlined above is achieved by the use of aseries of pressure sensitive bellows with the accompanying springs,diaphragms, or pistons, to control servo action of differential pressureacross a main dialator operation are required, such as constant 4cabinaltitude or constant dillerential pressure,

new bellows are therein added and thus additional complication in thesystem of such known regulators is encountered, and the complexity ofconstruction oi' such prior regulator units with their complex ninnberof moving parts contributes to their. poor operation and too numerousservice difficulties. In the cabin pressure regulators heretofore in usemuch complexity of moving parts and pressure sensitive devices,responsive both to cabin pressure and to flight pressure, has beenresorted to in order to accomplish one function, to vary the area of anoutilow orice or valve so as to restrict to a greater or lesserarranging the structure so that it can be equipped with standardpressure sensitive pilot and servo means whichl is then provided withadjustable air outflow orifice members having especially shapedcontours, and that are actuated by saidv y poses of this invention.

In the drawings:

rollers having their surface contours shaped to resemble rotary cams andarranged so as to present a predetermined orifice area between themembers at each flight altitude position of an associated servo means orabsolute pressure sensitive device. Similarly, a valve element ofproperly varying size and which is movable axially of the valve orifice,together with its supporting and actuating means, or some other variableori- Fig. l is a graph illustrative of the required cabin pressure orapparent cabin altitude versus ambient atmospheric pressure or airplaneflight altitude suitable for bombardment aircraft.v

Fig. 2 is a graph illustrative of such required cabin altitude versusairplane flight altitude suitable for fighter aircraft.

Fig. 3 is a graph illustrating suitable cabin pressures with relation toairplane flight altitude pressures indicated in in. Hg, and moreparticularly applicable to bombardment aircraft.'

Fig. 4 is an elevational view illustrating a cabin pressure regulatorembodying this invention in a desirable form of construction.

Fig. 5 is substantially 'a vertical sectional view of this 4form of theinvention, taken on line 5-5 of Fig. 4.

Fig.'6 is an enlarged sectional detail view, taken on line `B of Fig. 5.

Fig. '7 is a horizontal cross-sectional view, taken on line 1-1 of Fig.5j

Fig. 8 is a horizontal cross-sectional view, taken on line 8-8 of Fig.9, and being partly broken away, showing a modified form of theinvention which includes an automatic over-ride means.

Fig. 9 is a partial vertical sectional view of this modified form,takenon line 9--9 of Fig. 8.

Fig. 10 is a sectional detail view, taken on line l--ill of lig. 8.

The present invention vas disclosed herein pro' vides a simple anddirect means of varying the air outflow orifice area in proportion tothe ambient atmospheric pressure -or airplane flight altitude, so thatat anygiven airplane altitude the orifice area is adjusted automaticallyto thatwhich is known by previous calibration to be sufficientlyrestricted for the maintenance of the cabin pressure or cabin equivalentaltitude desired at that flight altitude; whereby complexity ofstructure is avoided, and the use of only one pressure sensitive deviceis thus required.

In this` invention the desired purpose will be served by the use of apair of non-cylindrical craft in which this unit is installed.

Y invention as illustrated in Figs. 4 to 7 inclusive,

flce means similar to a camera diaphragm, can be utilized herein andequipped with anv absolute A pressure sensitive actuating device so asto present large in the ascent from 0 to 8,000 ft., indicated'- by lineo--a, to avoid building up pressure in the cabin below said altitude,ands4 then diminish gradually to 35,000 ft., at c, to build up cabinpres-- sure at increasing rate, and then become larger and againprogressively smaller to- 40,000 ft., as indicated by the curvature online b-d in Fig. 3, and. will thereafter enlarge at an accelerated rate,as per line d-e.

If this same regulator presented by this invention is to' be 'installedin a` fighter or pursuit airplane whose pressure cabin requirements havebeen standardized in the manner shown in Fig. 2 of the drawings, theorifice members or cams will be replaced with others shaped so as toprovide a large initial area from 0 to 10,000 ft., indicated by line oh, and then gradually diminish to 18,000 ft., indicated by line h-, toybuild up cabin pressure, and then instantaneously .become larger at thepoint i, and again diminishing* thereafter, as indicated by line i-j.

In all these various installations the orifice area will change inproportion to flight altitude of the aircraft; -while the singlepressure responsive valve actuating means, which is preferably in theform of a diaphragm, and its operative connections, and also the singlepressure sensitive means, preferably in the form of an evacuatedbellows, will be standardized herein for all these installations. andwill then be equipped with and used along with the selected outfloworifice members which are particularly shaped and arranged to meet therequirements of the particular air- In the embodiment or particular formof this a pressure responsive device comprising a diaphragm is useddirectly as the actuating means by which the orifice area between thepair of companion orifice members is varied proportionally to flightaltitude or ambient atmospheric pressure; and an auxiliary evacuatedbellows is utilized as a pressure sensitive means to control absolutepressure in one chamber of this pressure responsive device.

This improved regulator is installed in the pressurized cabin orcompartment l, being mounted on the floor or on the air outlet pipe orthe like thereof, so that cabin air entering the regulator casing orhousing l 0 through its side wall screens I I, and passing across thevalve orifice area or valve opening 12, may be discharged through theair outilow mouth or diffuser section I3, into a space that is open toatmospheric pressure, such as the bomb bay, the luggage compartment, orthe like. The regulator housing comprises an upper' section Ilcontaining the pressure responsive valve actuating means including thediaphragm Il which is mounted across said section and is connected by ashaft I8 to a pair of yoke shaped members I1, each having a pair of endsI8 for operating a pair of spaced companion valve seat members or cammembers 2II; and in this illustrated form these cam members- 20 are inthe shape of. eccentric rollers and these ends I8 are in the shape ofrack ends operating a `pair of pinions I3 secured to said rollers 20 byuse of stub shafts 2I whereby the rollers are rotatably mounted in thehousing, so that the orifice area can be readily varied and adjustedautomatically through the action of the diaphragm and the resultantrotational movement and adjustment of said rollers 2l. These rotary cammembers or rollers have an irregular contour positioned at varyingdistances from the axis of rotation, substantially as indicated in thedrawings, to provide the predetermined variation and adjustment of theorifice area by rotating these members.

The ditl'user section or air outflow mouth I3 includes a pair ofinwardly curved wall portions 22 having the upper parts 23 pivotallymounted thereon by means 24 so as to be swingable with' the cams. Saidparts 23 are provided with rollers 25 at the upper ends for engaging thelower parts of the cam rollers 20; and additional rollers 26 engage theupper parts of said rollers 20, being carried on brackets 21 pivoted at2B and held in place by extendibly connected members 28 and amaaiAutomatic functioning of the regulator during night occurs as follows:

A chamber 53 provided above the diaphragm is vented to ambientatmosphere through a vent or channel II; while a chamber 52 beneath thediaphragm is vented to cabin pressure by the restricted vent 5Icontrolled by an adjustable valve 54, and by means of a channel 55 to alow pressure tube 56 which may be at the throat of the diiuser sectionor outlet oriiice 23, or may lead to an auxiliary vacuum source, notshown.

The restricted vent 53 permits entrance of cabin air at a reducedpressure into lower chamber 52, and a pressure sensitive means,preferably an evacuated bellows 58, is mounted on the lower wall in saidchamber and by its needle valve 59v operates to control the passage ofthe air from chamber 52 into channel l5 and to the low pressure areathrough tube I6. The action of the bellows 58 is such as to maintain aconstant absolute pressure kin chamber 52.

Ambient atmospheric pressure in the upper chamber 50 is opposed to theconstant pressure in the chamber 52 across the diaphragm I5. If theconstant absolute pressure in lower chamber 52 is maintained at anyconvenient value', such as 16.21 in. Hg absolute as depicted in thediagram in Fig. 1, the illustration in this igure shows by the lowerleft-hand shaded area how at the lower altitudes, below 16,000 ft., theambient atmospheric pressure communicated to the upper 30 attached,respectively, to a 4bracket 21 and to an arm 3| on swingable member 23.'A spring 32 on members 29 and 30 urges the members 21 and.3I apart tomaintain rollers 25 and 26 in operative close contact with cam members20.

The valve means for regulating the orifice area further comprises amovable valve element or closure member 35 which is substantially ovalshaped in vertical cross section, and it is mounted to have itswedge-shaped end movable in the oriilce'between the spaced cam rollers20, adapted to restrict the orice to the desired extent and also toclose the same. This valve member 35 includes guide lugs or endextensions 36 movable in channel means 31 provided on the sides of theregulator housing III, being thereby guided evenly in its verticalmovement and adjustment between the rollers 20.

The valve member Il is operatively supported by means of a lever 33which is pivoted on a bracket 4I, and the notched end 4oi said leverengages a pin Il mounted in a slot I2 in member Il.

Manual control means or over-ride means is provided for adjusting thearea of the orifice, and it includes a knob or wheel 43 operating ashaft M which is provided with a screw thread or worm whereby it engagesthe ratched end ll of lever 3l, being thus adapted to hold the lever andthereby the valve member 3l normally in its predetermined position, andalso to adjust said lever and valve member and thereby regulate theoutilow orifice manually at will. The knob is suitably marked forindicating its position or adjustment for the valve member 33, and theknob I3 and the shaft u are locked in position by means of a lock nut l1actuated by the handle 4l thereon.v

resistance, are provided and mounted, respecchamber 50 will exceed theconstant pressure maintained in lower chamber 52, and shows by the upperright-hand shaded area how at higher altitudes, above 16,000 ft., theconstant pressure in said lower chamber 52 will exceed ight pressurecontained in the upper chamber 50. Then, since calibrated springs and6I, of the proper tively in chambers 50 and 52, to counterbalance thediaphragm, it will be apparent that a given axial or vertical positionwill be assumed by said diaphragm Ilfor each upper chamber pressurecondition, that is to say, for each flight altitude condition` orpressure, since the upper chamber 50 is open through vent 5I to ambientatmospheric pressure. t

By'action of shaft I6, yoke I1, rack i8 and pinions I9 a differentrotational position of the cam members or rollers 20 will be providedfor each axial or vertical position taken by the diaphragm I5.Therefore, a predetermined given position of cam members 20 being asumedat each Hight altitude, thecabin altitude maintained will be dependentupon the particular calibrated shape and consequent outilow oriiice areaprovided by the cam members used.

In aircraft dives or climbs the rate of cabin altitude change will beproportional to the rate at which the changing night pressure or ambientatmospheric pressure is communicated y to the upper chamber 50 throughthe vent line or channel 5I which is in comunication with theatmosphere; Thus, by installing a valve 63 in the vent line 5I, thevalve being equipped with a gauged controlv handle 84, said vent linecan be throttled by operating the handle il to limit the rate of presurechange effected in upper chamber 50, and consequently, to limitrthe rateof change of cabin pressure. f

It is apparent from the above disclosure that advantages are attainedwith this invention, as the construction o! this regulator is greatlysimpliiled in its manufacture and also in ease of maintenance, since itrequires only one pressure 7 sensitive device, compared tof'severalother such devices in the previously constructed regulators.' In myinvention different air outow orifice j members or cam members may beused, along with the general or standard pressure sensitive pilot andservo means to meet various installation requirements, whereas in theknown prior regulators the pressure sensitive pilot means must berearranged and reassigned for each new type of installation. Improvedperformance is also had as a result of my simplified construction.

Normally, during automatic cabin pressure 8 guide fingers |51 at theinner end movable in said slot |42 in valve member |35 and beingprovided with a notch |53 at the junction of said fingers.

' An operating handle |33 is pivoted in and extends from the extension|23, and a pin |13 at its inner end is movable in a vertical slotprovided in an regulation the cam members or valve seat members 20 ofthe air outflow valve means are held in the predetermined position bylinkage |5, I1, |5 and, under changing altitude and conditions, are`automatically operable by the associated servov means; while the valvemember 35 is normally held in its stationary position by the connectedlever 39 and its ratchet end 45 retained by worm 45 on shaft 44. 'I'hevalve member 35, however, is adjustable by the manual Vover-ride meansbyturning the knob 45 on shaft 44 with its worm 45 to actuate the ratchet45 with its lever 39 and thereby the valve member 35, as disclosedabove.

An automatic over-ride means may be-provided additionally in thisinvention, as indicated in the modified form illustrated in Figs. 8, 9,and 10, showing how such an automatic over-ride means may be installedherein, and may be included to operate in place of the manual over-ridemeans for automatically regulating the area of the valve orifice 2 byadjusting the valve member |35.

In this modified form the regulator is similar in its main structure tothat disclosed above, and it comprises a similar housing ||0 adapted tobe .mounted in the cabin |09. It includes the rotary cam members orvalve seat members |23 which are operable to regulate the air outfloworifice |2, and are supported on the upper wall .portions |23 which areswingably mounted by pivot means |24 on the stationary wall portions |22of the air outow mouth or diffuser section ||3 wherefrom the air flowsto the ambient atmosphere.

This valve member |35 is provided with end extensions |36 movable inchannel means |31 at the sides of housing H5, and a spring |33 ispreferably included in each channel to compensate partly for the weightof valve member 35. A lever |39 is pivotally mounted on a bracket |45,and has its inner end movable in a slot |42 in Lmember |35, while anotch in said inner end of matic over-ride means is included or renderedoperative then the manual over-ride means is excluded or renderedinoperative. This automatic means comprisesa housing extension|29provided on the regulator housing ||3, and it includes a chamber |35having a diaphragm |3| extending across it and providing a lower-chamber portion |32 beneath the same. .A stem. |5| extends from thediaphragm to an upper chamberv Y |52 in the extension |23 and isconnected by a pin |53 to a lever shaft |54, said pin being movable in aslot |55 in the shaft. Said shaft extends through a universally movableball pivot |33 into the air outflow orifice ||2 and has a pair of endarm |1| at the outer end of` shaft |54.

vln the operation of this automatic valve means. when handle |59 is inthe operative position, as shown in full lines in Fig. 9, the valvemember |35 is subjected only to the action of the manual over-ride meansassociated with lever |33. while pin |4| is seated in the notch providedin the end of the lever |39. Whenever it is desired to bring theautomatic over-ride means into action, then handle |59 is shiftedinwardly to the position shown in dotted lines in Fig. 9, and the endarm |1| of shaft |54 is thereby shifted inwardly, from its full lineposition to the dotted line position as shown in said Fig. 9. The shaft|34 thereby slides its slot |55 along pin |53 and brings its guidefingers |51 into the active position, as indicated in dotted lines inVsaid figure, thereby shifting the pin |4| horizontally through the slotThe chamber |30 above the diaphragm |3| is vented through a channel m tothe htmosphere; while the lower chamber |32 below the diaphragm isvented through a port or opening |13 to the cabin. A calibrated spring|14 in chamber |35 bears on diaphragm |3|, thus aiding in controlber|35, so as to limit the differential pressure between cabin and ambientatmosphere to any given value. i

It will be 'noted that the lever shaft |34 is operatively connected tothe stem |5| of the diaphragm |3| and is thereby movable verticallythrough the action of the diaphragm. This diaphragm |3| with itsconnections will thus function, by excessive cabin pressure, to raisethe stem |5| and thereby raise the outer end of the shaft |54, while theinner end of said shaft with the valve member |35 is being lowered, somsto enlarge the air outflow orifice I2 to expedite the outflow ofpressurized air from the cabin. Similarly, when the cabin pressure isdecreased, then the diaphragm |3| is lowered together with its stem |5|and the outer part of shaft |34, thereby raising the inner end of saidshaft and the valve member' |35, so as to restrict the outflow orifice||2 and restrict the outflow, of air from the cabin.

This modified form of my invention is provided, like the first describedform, with the servo means whereby the orifice area of the regulator isautomatically controlled through the action of the ambient yatmosphericpressure in the upper chamber of the regulator housing, admitted throughchannel |5|, assisted by the regulated air in its lower chamber whichmay flow .out

through the channel to a low pressure area, as in the abovedescribedform, and themanual over-ride means is also similarly providedand arranged herein, and operated through'shaft |44. However, inaddition thereto this form is provided with the automatic over-ride.means which, upon its inclusion by operation of handle |33, is actuatedby the diaphragm |3| under influence lof the opposingpressures of thecabin equivalent altitude and of the ambient atmospheric altitude aidedby calibrated spring |14.

Iclaim: 1. A pressure regulator for a pressurized aircraft cabin,comprising air, outflow means including a plurality of associated valvemembers adjustable for regulating the outflow of air from the cabin, atleast one of said valve members being a cam roller rotary for varyingthe outflow area,`means associated with said outflow means andresponsive to ambient atmospheric pressure for automatically actuatingthe cam roller to regulate the outflow area andcontrol cabin pressurethereby, said pressure responsive means being arranged and constructedto render it responsive in all its phases of automatic action alone toabsolute atmospheric pressure, and over-ride means to adjust another ofsaid valve members and modify the outflow area at will.

2. A pressure regulator 'for a pressurized aircraft cabin, comprisingair outflow means including spaced apart similarly shaped and jointlyoperated companion valve seat means and associated valve closure meansfor regulating the area of said outflow means, means responsive toambient atmospheric pressure to adjust one lof s said valve means andvary the air outflow area in accord with said atmospheric pressure,whereby to automatically maintain the selected cabin pressure, andover-ride means for adjusting the other of said valve means to modifythe outflow area at will and vary the pressure differential between thecabin and the ambient atmosphere.

3. A pressure regulator for a pressurized aircraft cabin, comprising aplurality of valve means adjustable for controlling the outflow of airfrom the cabin, a plurality of chambers provided with pressureresponsive means therebetween, one of the chambers being vented to thecabin and another of the chambers being vented to the atmosphere, meanswhereby to retrict said vents to limit the rate of change of cabinpressure, a

channel leading from the cabin vented chamber to a low pressure area,pressure sensitive means in the last said chamber adaptedgto control theoutflow of chamber air through said channel and maintain a constantabsolute pressure in said chamber, means operatively connecting saidpressure responsive means with one of said valve means for automaticallyadjusting the outflow area and controlling cabin pressure thereby, saidvalve control means being'responsive in all its phases of automaticaction alone to absolute atmospheric pressure, and over-ride means foradjusting the other of said valve means at will to vary the pressuredifferential between the cabin and the ambient atmosphere.

4. A pressure regulator for a pressurized aircraft cabin, said regulatorcomprising air outow means including spaced valve seat members whichhave cam like contours and are rotary, adjustable valve closure meansassociated with said members, means responsive to ambient atmosphericpressure to rotate said valve seat members and to vary the outflow areatherebetween in proportion to said atmospheric pressure and maintain aselected cabin pressure, and manually actul ated over-ride means wherebyto actuate said closure means at will and vary the pressure differentialbetweenlthe cabinv and the ambient atmosphere.

5. A pressure regulator for a pressurized airan orifice therebetween forexhausting air to atmosphere, said members being particularly shaped andadjustable for modifying the outflow area to suit the selected cabinaltitude pressure and are also mounted to be readily removable andexchangeable for accommodating different flight conditions, adjustablevalve closure means cooperating with said seat members, means responsiveto ambient atmospheric pressure to adjust said valve seat members andvary the outflow area thereof in accord with said atmospheric .pressureand maintain a selected cabin pressure, and lmanually actuated over-ridemeans whereby to adjust said closure means and thereby the outflow areaand vary the pressure differential between the cabin and the ambientatmosphere.

6. A pressure regulator for a pressurized airs craft cabin, saidregulator comprising an air outflow oriilce which includes closure meanscontaining spaced companion seat members each having a contour soarranged and shaped and being adjustable for varying the outflow area soas to suit the selected varying cabin altitude pressures, closure meanscooperating with said seat membersladapted to regulate or to close theoutflow orifice, servo means including opposite chambers, one subject torestricted cabin pressure and the other to ambient atmospheric pressure,said servo means being connected with said members for actuating thesame automatically, pressure sensitive means to control the pressure insaid cabin-pressure chamber and regulate the action of said servo means,and manually actuated override means adapted to adjust the closuremeans, whereby to regulatethe outflow area of the orice and maintain theselected cabin pressure at various altitudes.

7. A pressure regulator for a pressurized aircraft cabin, said regulatorcomprising air outflow means including similar cam members which havetheirgcontours shaped and are adjustable for modifying the outflow areato suit the selected cabin altitude pressure, said members being readilyremovable and exchangeable for accommodating different flightconditions, valve closure means cooperating with said cam members, meansresponsive tov ambient atmospheric presure to adJust said cam membersand vary the outflow area in accordance with said atmospheric pressurefor automatically maintaining a selected cabin pressure, and manuallyactuated over-ride means whereby to adjust said closure means at willand vary the pressure differential between the cabin and the ambientatmosphere.

8. A pressure regulator for a pressurized aircraft cabin, said regulatorcomprising spaced companion cam rollers providing an air outflow orificetherebetween, each cam roller having a contour arranged and shaped andbeing adjustable by rotation for varying the outflow orifice, valveclosure means cooperatingwith said cam rollers, servo means includingchambers one of which is subjected' to restricted cabin pressure and theother to ambient atmospheric pressure, said servo means beingoperatively connected with the cam rollers for actuating the sameautomatically, evacuated bellows to regulate the action of said servomeans, and manually actuated over-ride means adapted normally to sup`port the closure means and whereby to selectively adiust the outflowarea of the orifice and vary the pressure differential between the cabinand the ambient atmosphere at various altitudes.

9. A pressure regulator for a pressurized an.

^ 11 craft cabin, comprising a plurality of associated valve meansadjustable for varying the outflow y area and controlling the outilow ofair from the cabin, a plurality of chambers with pressure responsivemeans therebetween, one of the chambers having a valve-controlledpassage venting to the cabin and also a passage venting to` a lowpressure area, another of the chambers having a passage venting to theatmosphere, pressure sensitive means in said cabin-pressure chamber toregulate said vent to the low pressure area and maintain a constantabsolute pressure in said chamber, manually controlled valve means inthe atmosphere-venting passage adapted toregulate the rate of change ofcabin pressure, means operatively connecting said pressure responsivemeans with one of said valve means for automatically adjusting theoutilow areaand control- ,wedge-shaped closure means movable between therollers, means responsive to ambient atmospheric pressure associatedwith said rollers and being arranged and constructed to automaticallyrotate and adjust them for varying the air outiiow area therebetween inaccordance with said atmospheric pressure, thereby maintaining theselected cabin pressiue, and over-ride means normally supporting saidclosure means and whereby to actuate the same and adjust the outilowarea and vary the pressure differential between the cabin and theambient atmosphere.

11. The subject matter set forth in claim 10, wherein' said over-ridemeans comprises an override which is normally manually operable andfurther comprises an over-ride which is automatically operable and alsocontains means which is operable at will to exclude said manual overldeand include said automatic over-ride for ac- 12. A pressure regulatorfor apressurized aircraft cabin, said regulator comprising air outflowmeans including valve seat members which are spaced apart in an outletto form an exhaust oriilce therebetween and which have their contoursirregularly shaped, adjustable valve means associated with said menibersto restrict the outow Amembers and to vary the outiiow area thereof inproportion to the ambient atmospheric pressure and maintain a selectedcabin pressure, manually actuated over-ride means whereby normally toadjust said valve means and vary the pressure differential between thecabin and the ambient atmosphere, auxiliary over-ride means responsiveto the dierential between ambient atmospheric pressure and cabinpressure for. automatically regulating said valve means, and meansoperable to exclude the manual over-ride means and include the automaticover-ride means for action.

13. A pressure regulator for a pressurized airl craft cabin, saidregulator comprising air outilow area therebetween, means responsive toambient Y means including companion cam members which have theircontours especially shaped and are adjustable for modifying the outowarea to suit the selected cabin altitude pressure, said cam membersbeing removable and exchangeable for accommodating diiferent nightconditions, ad?

pressure, manually actuated over-ride means whereby to adjust saidclosure means and vary the pressure differential between the cabin andthe ambient atmosphere, and automatic override means to be actuated atwill for including it in. place of the manual over-ride means.

14. A pressure regulator for a pressurized aircraft cabin, saidregulator comprising anair outflow oriilce whichl includes valve meanscontaining spaced'companion cam rollers having the contours so arrangedand shaped and being rotatively adjustable for varying the outflow areatherebetween so as to suit the varying selected cabin altitudepressures, means cooperating with said rollers adapted to restrict or toclose the outflow orliice, servo means including opposite chambers, onesubject to restricted cabin pressure and the other to ambientatmospheric pressure, said servo means being connected with said rollersfor ac-` tuating the same automatically, pressure sensitive bellows toregulate said servo means, manually actuad over-ride means normallyoperative to support and to adjust the closing means. whereby toregulate the outflow area. of the oriilce and maintain-the selectedcabin pressure at various altitudes, auxiliary over-ride means inclusivefor automatically regulating said valve closure means, and meansoperable to exclude the manual over-ride means and include the automaticover-ride means.

nonnar J. scmtonnna.

